CN107137242A - A kind of skin care compositions and methods - Google Patents

Abstract

The invention belongs to the field of skin care compositions and discloses a skin care composition comprising (0.1 to 3) wt% of a carboxylic acid copolymer, and the carboxylic acid copolymer is poly(α,β-unsaturated carboxylic acid /N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer and/or poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer. The skin care composition of the present invention can effectively improve the skin care effect.

Description

A kind of skin care composition

technical field

The invention relates to the field of skin care compositions, in particular to a skin care composition capable of effectively improving skin care effects.

Background technique

At present, rheology modifiers used in skin care products are mainly divided into synthetic polymers and natural polymer materials, the former such as carbomer resin, glycerin polyacrylate, etc. dishes etc. The two types of substances have their own characteristics. Synthetic polymers usually have excellent suspending and thickening capabilities, but the skin feels too moist (water) and refreshing after use, which can easily give consumers the illusion of low added value of the product. Natural materials have a richer and more layered feeling in terms of skin feel, but natural materials have weak thickening ability, high addition amount, low transparency, poor suspension ability, and high price. In view of the above analysis, a polymer with good thickening and suspending ability and excellent skin feel will have broad market potential.

As is well known to those skilled in the art, synthetic polymer thickeners such as carbo resins can be used as sustained-release agents in eye drops, creams, gels and other products to prolong the action time of drugs or active components. However, carbo resin does not have the ability to form a continuous film, and its adhesion to skin and other surfaces is low, so it is easy to fall off from skin and other surfaces after coating, so its slow release and prolonging the action time of active components will be greatly reduced.

Patent ZL2005800430583 discloses a rheology modifier/skin care resin which is a cross-linked linear poly(vinylamide/polymerizable carboxylic acid) copolymer exhibiting favorable high viscosity and long-lasting curl retention for hair care performance. This solution can provide better film-forming performance, but the problem is that it is difficult to disperse the resin in water. It is necessary to add part of the neutralizer to the water first, and then slowly sprinkle the polymer while stirring. It takes 60 minutes to disperse. , if the polymer is "poured", the dispersion time is doubled. Moreover, it cannot form a relatively stable salt-resistant cross-linked structure, which will cause the gel to lose water and reduce its viscosity after contacting the skin.

The above-mentioned defects will lead to a significant reduction in the actual application performance of skin care products or cosmetics.

Contents of the invention

The invention aims to provide a preparation method of the skin care composition which can effectively improve the skin care effect.

The solution of the present invention is specifically: a skin care composition comprising (0.1 to 3) wt% carboxylic acid copolymer used as a rheology modifier and a film-forming agent, and the carboxylic acid copolymer is poly( α, β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer and/or poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer thing;

In the poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer, α, β-unsaturated carboxylic acid, N-alkylacrylamide and N- The mass ratio of vinylpyrrolidone is 65-87:3-18:4-25;

The mass ratio of α, β-unsaturated carboxylic acid and N-alkylacrylamide in the poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer is 75-95:6 ~18.

In the above skin care composition, the skin care composition is a skin care gel, an anti-wrinkle composition, a skin care lotion, and a skin care cream/cream.

In the above skin care composition, the composition includes an appropriate amount of neutralizing agent, other cosmetic and/or skin care acceptable bases and the balance of deionized water.

The acceptable matrix described in the present invention has many optional types, such as various plant extracts such as skin care active ingredients aloe powder, white fungus extract, witch hazel extract, purslane extract, etc., and can also be moisturizing Components such as glycerin, when the skin care composition of the present invention is a cream, an appropriate amount of surfactant and the like are also required.

In the above skin care composition, the chemical formula of the alkyl group in the N-alkylacrylamide is C _n H _2n+1 , where n=4-12.

In the above skin care composition, the N-alkylacrylamide is N-dodecylacrylamide, N-octylacrylamide, N-tert-octylacrylamide, N-heptylacrylamide, One or more combinations of phenylacrylamide, N-butylacrylamide, and N-tert-butylacrylamide.

In the above skin care composition, the α, β-unsaturated carboxylic acid is a combination of one or more of (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid .

In the above skin care composition, the α, β-unsaturated carboxylic acid is acrylic acid.

In the above skin care composition, the cross-linking monomer used in the carboxylic acid copolymer accounts for 1.0-3.2 wt% of the total weight of the comonomer.

In the above skin care composition, the crosslinking monomer is one or more combinations of pentaerythritol triallyl ether, diethylene glycol diallyl ether or sucrose allyl ether.

The beneficial effects of the present invention are:

Poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer and/or poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide) used ) crosslinked copolymers function as rheology modifiers and film formers. The skin care composition of the present invention has suitable viscosity and pleasant elasticity for users, is easy to twist, has a large amount of lift, smooth skin feeling, and does not become thin when applied on the skin. After drying, it can form a continuous film on the skin surface, so it can play the role of wrinkle removal, isolation of air pollutants and prolonging the action time of active ingredients.

Description of drawings

Fig. 1 is the polymer of embodiment A2 of the present invention and the wetting contrast figure of commercially available product;

Fig. 2 is the polymer of embodiment A2 of the present invention and the stirring dispersion figure of commercially available product;

Figure 3 is a neutralization comparison chart of the polymer of Example A2 of the present invention and commercially available products.

detailed description

The technical solutions of the present invention will be further described in detail below in conjunction with specific embodiments, but this does not constitute any limitation to the present invention.

In order to describe the present invention more clearly, the following examples are cited to illustrate the superiority of the present invention.

Composition Example

Embodiment 1 Skin care aloe vera gel, formula is as follows table one.

Table 1 Formula list of skin care aloe vera gel

Sprinkle the poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer into deionized water under stirring, stir to disperse evenly, then add the remaining components in turn and stir evenly to obtain skin care aloe vera gel.

Example 2 The instant anti-wrinkle composition, the formula is as shown in Table 2.

Table 2 Formula table of instant anti-wrinkle composition

Sprinkle poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer into deionized water under stirring, stir to disperse evenly, then add the remaining components one by one and stir evenly , to obtain an instant anti-wrinkle composition.

Embodiment 3 skin care essence, formula is as follows table three.

Table 3 Formula list of skin care essence

Sprinkle poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer into deionized water under stirring, stir to disperse evenly, then add the remaining components one by one and stir evenly , get skin care essence.

Embodiment 4 sunscreen, formula is as follows table four.

Table 4 Formula list of skin care essence

Prepare phases A and B separately and heat to 75°C. Slowly inject phase B into phase A under stirring, homogenize for 10 minutes, cool to 45°C, add phase C, and stir evenly to obtain sunscreen. This sunscreen uses the film-forming ability of poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer after drying to form a layer of sunscreen film on the surface of the skin, which can prolong the residence time of the sunscreen and Provide some waterproof performance.

Embodiment 5 liquid eyeliner, formula is as follows Table 5.

Table 5 Liquid Eyeliner Formula Table

Prepare phases A and D separately and heat to 85°C. Add phases B and C to phase A, then slowly inject phase B into phase A while stirring, homogenize for 10 minutes, cool to 55°C, add phase E, stir well, then cool down to 45°C, stir well to get liquid eyeliner, Viscosity 75000mPa·s.

Embodiment 6 night cream composition, formula is as follows table six.

Table 6 Night Cream Composition Formulation Table

Prepare phases A, B, and D respectively, add phase B into phase A while stirring, homogenize for 10 minutes, then add the rest of the phases, stir well to obtain a night cream composition.

Comparative example 1

According to the skin care aloe gel formula and preparation method of Example 1, the skin care aloe gel of this comparative example 1 is prepared. The difference from Example 1 is that the comparative example A1 polymer is sprinkled into deionized water under stirring of the embodiment, and stirred to disperse Homogeneous, then add the remaining ingredients one by one and stir well.

Comparative example 2

According to the instant anti-wrinkle composition and preparation method of Example 2, the instant anti-wrinkle composition of this Comparative Example 2 was prepared, the difference from Example 2 was that the polymer of Comparative Example A2 was sprinkled into deionized water under stirring of the Example , stir to disperse evenly, then add the remaining components in turn and stir evenly.

Comparative example 3

This comparative example 3 is skin care essence, and its composition is as follows table seven

Table 7 Formula table of skin care essence

When preparing, add the above components in order and mix them evenly.

Performance parameters of skin care composition

The skin care aloe vera gel, instant anti-wrinkle composition, and skin care essence prepared in Examples 1-3 and Comparative Examples 1-3 were tested (see Table 9 for detailed rules on skin feeling scores), and the results after the test are shown in Table 8

The performance test result of table eight embodiment 1-3 and comparative example 1-3

Examples 1, 2 and Comparative Examples 1, 2 illustrate that the present invention has obvious advantages compared with traditional polyacrylic acid thickeners in skin care applications, especially the unique skin care products that can be given slippery, invariable thinning and water-resolving during application. feel. Example 2 can form a film after drying, which can tighten the skin and remove wrinkles to a certain extent; while the traditional polyacrylic acid thickener (comparative example 2) does not have this function. Example 3 is an essence composition, which can form a film on the skin surface after drying, which can not only give users a feeling of skin firmness, but also prolong the action time of the active ingredients in the essence, and play a certain slow-release effect .

The preparation method of the polymer described above and some properties of the polymer are as follows:

The preparation method of cross-linked copolymer:

Preparation of poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer:

Example A1

Take by weighing 3g N-lauryl acrylamide, 25g N-vinylpyrrolidone, 2.9g polyoxyethylene 30 dipolyhydroxystearate, 2.8g pentaerythritol triallyl ether, 0.5g peroxydicarbonate di( 3-methoxybutyl ester), above-mentioned raw material is dissolved in 65.8g acrylic acid and is mixed with raw material solution stand-by. Add 283.3g of cyclohexane and 283.4g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Example A2

Weigh 6g N-tert-butylacrylamide, 13g N-vinylpyrrolidone, 2.4g Span-80, 0.8g pentaerythritol triallyl ether, 0.3g sucrose allyl ether, 0.4g peroxydicarbonate di( 3-methoxybutyl ester), above-mentioned raw material is dissolved in 77.1g acrylic acid and is mixed with raw material solution stand-by. Add 501.9g of cyclohexane and 167.3g of butyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 45°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Example A3

Weigh 5g N-tert-octyl acrylamide, 4g N-vinylpyrrolidone, 2g polyoxyethylene 30 dipolyhydroxystearate, 2.1g pentaerythritol triallyl ether, 0.3g peroxydicarbonate di(3- methoxybutyl ester), above-mentioned raw material is dissolved in 86.6g acrylic acid and is mixed with raw material solution stand-by. Add 160g of cyclohexane and 240g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 55°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Example A4

Weigh 18g N-tert-butylacrylamide, 8g N-vinylpyrrolidone, 5g polyoxyethylene 30 dipolyhydroxystearate, 3g pentaerythritol triallyl ether, 0.4g peroxydicarbonate bis(3-methyl oxybutyl ester), the above-mentioned raw material is dissolved in 65.6g acrylic acid and is mixed with the raw material solution stand-by. Add 131.3g of cyclohexane and 393.7g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen while stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Example A5

Weigh 12g N-lauryl acrylamide, 9g N-vinylpyrrolidone, 3.9g polyoxyethylene 30 dipolyhydroxystearate, 2.5g sucrose allyl ether, 0.6g peroxydicarbonate di(2 - ethylhexyl ester), 72g acrylic acid, above-mentioned raw material is dissolved in 135g n-hexane and 315g ethyl acetate and is mixed with raw material solution stand-by. Add 135g of cyclohexane and 315g of propyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Example A6

Weigh 9g N-lauryl acrylamide, 15g N-vinylpyrrolidone, 0.6g polyoxyethylene 30 dipolyhydroxystearate, 2g Span-80, 0.9g sucrose allyl ether, 1g pentaerythritol tris Allyl ether, 0.4g bis(2-ethylhexyl)peroxydicarbonate, the above raw materials were dissolved in 70.1g acrylic acid and 1g methacrylic acid to prepare a raw material solution for use. Add 307.1 g of cyclohexane and 307.1 g of propyl acetate into a 1000 ml flask, pass nitrogen to remove oxygen while stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Comparative example A1

Weigh 2.5g polyoxyethylene 30 dipolyhydroxystearate, 1.4g pentaerythritol triallyl ether, 0.4g peroxydicarbonate bis(3-methoxybutyl), and dissolve the above raw materials in 95.7g acrylic acid Prepared as a raw material solution for use. Add 334.6g of cyclohexane and 334.6g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Comparative example A2

Take by weighing 25g N-vinylpyrrolidone, 2.9g polyoxyethylene 30 two polyhydroxystearate, 2.8g pentaerythritol triallyl ether, 0.5g peroxydicarbonate two (3-methoxybutyl), will The above raw materials were dissolved in 68.8g of acrylic acid to prepare a raw material solution for use. Add 283.3g of cyclohexane and 283.4g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100°C to obtain a fine white copolymer thickener powder.

Summary: In this embodiment A1-A6, N-alkylacrylamide and N-vinylpyrrolidone are used as functional monomers. N-alkylacrylamide has a hydrophobic alkyl group, while N-vinylpyrrolidone has hydrophilicity. By adjusting the ratio of the two, polymer particles with suitable surface hydrophilicity and hydrophobicity can be obtained, and at the same time, certain surfactants can be given to the polymer. Therefore, it is very beneficial to the wetting and dispersion of polymers in water. N-alkyl acrylamide is used as a functional monomer, and an amide bond is also introduced while introducing a hydrophobic group. Hydrophobic groups can bring hydrophobic association, which is due to the aggregation of hydrophobic groups due to hydrophobic interactions, resulting in intramolecular and intermolecular associations; the introduction of acrylamide monomers not only improves In addition to the skin affinity of the polymer, it also provides a large number of hydrogen bond donors and acceptors. Hydrophobic association and hydrogen bonding form a higher-level cross-linked network structure within and between molecules of the polymer. This structure is insensitive to external ions and can effectively resist dehydration and viscosity reduction of the gel due to salt on the skin surface Equivalent effects; at the same time, this structure can improve the cohesion of the polymer gel, endow the polymer gel with moderate elasticity and extensibility macroscopically, and easily adhere to the skin. At the same time, both N-alkylacrylamide and N-vinylpyrrolidone can provide good film-forming ability, and we found that the polymer gel has a pleasant film-forming and firm feeling after being applied to the skin. In addition, we surprisingly found that the copolymerized polymer hydrogel has good transparency.

In this embodiment A1-A6, the precipitation polymerization method of "starvation dropping" was adopted, while the traditional method for preparing polycarboxylic acid thickener was to place all the reactants except the initiator in the reactor, and add the initiator dropwise during the reaction. Compared with the traditional method, the heat release during the polymerization process of the "starvation drop" method is stable and easy to control, and the phenomenon of implosion is not easy to occur; in addition, as is well known to researchers in the field, the "starvation drop" method can effectively inhibit the polymerization of each monomer in the copolymerization reaction. Homopolymerization tendency is beneficial to obtain homogeneous copolymerized polymers. We found that the polycarboxylic acid thickener obtained by the "starvation drop" method has better light transmittance and fineness than the traditional method, and the appearance is greatly improved. Compared with the "seed" precipitation polymerization method that needs to synthesize "seed" first, the "starvation drop" method can obtain products with similar properties, and the synthesis steps are greatly simplified

Preparation of poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer:

Example B1

Weigh 6g N-lauryl acrylamide, 2.9g polyoxyethylene 30 dipolyhydroxystearate, 1.1g pentaerythritol triallyl ether, 0.5g bis(3-methoxybutyl peroxydicarbonate) ), above-mentioned raw material is dissolved in 89.5g acrylic acid and is mixed with raw material solution stand-by. Add 283.3g of cyclohexane and 283.3g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Example B2

Weigh 10g N-tert-butylacrylamide, 3.5g Span-80, 0.9g pentaerythritol triallyl ether, 0.5g sucrose allyl ether, 0.5g bis(3-methoxybutyl peroxydicarbonate) ), above-mentioned raw material is dissolved in 84.7g acrylic acid and is mixed with raw material solution stand-by. Add 393.8g of cyclohexane and 131.2g of butyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 45°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Example B3

Take by weighing 15g N-tert-octyl acrylamide, 5g polyoxyethylene 30 dipolyhydroxystearate, 2.1g pentaerythritol triallyl ether, 0.3g peroxydicarbonate bis(3-methoxybutyl), The above raw materials were dissolved in 77.6 g of acrylic acid to prepare a raw material solution for use. Add 160g of cyclohexane and 240g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 55°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Example B4

Take by weighing 18g N-tert-butylacrylamide, 2.8g polyoxyethylene 30 dipolyhydroxystearate, 3g pentaerythritol triallyl ether, 0.4g peroxydicarbonate bis(3-methoxybutyl), The above raw materials were dissolved in 75.8 g of acrylic acid to prepare a raw material solution for use. Add 167.3g of cyclohexane and 501.9g of ethyl acetate into a 1000ml flask, pass nitrogen to remove oxygen while stirring, and raise the temperature to 55°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Example B5

Take by weighing 12g N-lauryl acrylamide, 2g polyoxyethylene 30 dipolyhydroxystearate, 2.5g sucrose allyl ether, 0.6g peroxydicarbonate bis(2-ethylhexyl), 82.9 g acrylic acid, above-mentioned raw material is dissolved in 135g n-hexane and 315g ethyl acetate and is mixed with raw material solution stand-by. Add 135g of cyclohexane and 315g of propyl acetate into a 1000ml flask, pass nitrogen to remove oxygen under stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Example B6

Weigh 11g N-lauryl acrylamide, 0.6g polyoxyethylene 30 dipolyhydroxystearate, 2g Span-80, 0.9g sucrose allyl ether, 1g pentaerythritol triallyl ether, 0.4g For bis(2-ethylhexyl) peroxydicarbonate, the above raw materials were dissolved in 83.1 g of acrylic acid and 1 g of methacrylic acid to prepare a raw material solution for use. Add 307.1 g of cyclohexane and 307.1 g of propyl acetate into a 1000 ml flask, pass nitrogen to remove oxygen while stirring, and raise the temperature to 50°C. Add the above-mentioned raw material solution dropwise to the flask for 3 hours. During the process, the solution becomes turbid, white precipitates are formed, and the viscosity of the system rises. Change the stirring speed in time to maintain a good stirring effect. After the dropwise addition, the temperature was raised to 60° C. for 2 h.

The polymer suspension was transferred to a one-necked flask, and the solvent was removed by vacuum rotary evaporation at 90-100° C. to obtain a fine white carboxylic acid copolymer thickener powder.

Summary: In this example B1-B6, N-alkylacrylamide was used as the functional monomer, and the amide bond was also introduced while introducing the hydrophobic group. Hydrophobic groups can bring hydrophobic association, which is due to the aggregation of hydrophobic groups due to hydrophobic interactions, resulting in intramolecular and intermolecular associations; the introduction of acrylamide monomers not only improves In addition to the skin affinity of the polymer, it also provides a large number of hydrogen bond donors and acceptors. Hydrophobic association and hydrogen bonding form a higher-level cross-linked network structure within and between the molecules of the polymer. This structure is insensitive to external ions and can effectively resist dehydration and viscosity reduction of the gel due to salt on the skin surface Equivalent effect; at the same time, this structure can improve the cohesion of the polymer gel, endow the polymer gel with moderate elasticity and extensibility macroscopically, and be easy to adhere to the skin. At the same time, we found that the polymer gel is coated on Skin has a pleasant film-forming, firming feel afterward. The above characteristics are not available in traditional polycarboxylate thickeners.

In this example B1-B6, the "starvation drop" precipitation polymerization method is adopted, while the traditional method of preparing polycarboxylic acid thickener is to place all the reactants except the initiator in the reactor, and add the initiator dropwise during the reaction. Compared with the traditional method, the heat release during the polymerization process of the "starvation drop" method is stable and easy to control, and the phenomenon of implosion is not easy to occur; in addition, as is well known to researchers in the field, the "starvation drop" method can effectively inhibit the polymerization of each monomer in the copolymerization reaction. Homopolymerization tendency is beneficial to obtain homogeneous copolymerized polymers. We found that the polycarboxylic acid thickener obtained by the "starvation drop" method has better light transmittance and fineness than that prepared by the traditional method, and the appearance is greatly improved. Compared with the "seed" precipitation polymerization method that needs to synthesize "seeds", the "starvation drop" method can obtain products with similar properties, and the synthesis steps are greatly simplified.

Performance Testing

Test Methods:

1. Determination of wetting time at 25°C

Weigh 100g of deionized water into a 250mL beaker, seal it with plastic wrap, put it in a constant temperature water bath, and keep the temperature at 25±0.5°C. Accurately weigh (0.5±0.005)g sample with a balance, quickly and evenly sprinkle it on the water surface in the beaker, control the sample spraying time within 5-10s, and ensure that the copolymer thickener powder is evenly scattered on the water surface Shake the beaker gently by hand before the polymer thickener is wetted to make the copolymer thickener even and smooth. As soon as the copolymer thickener powder begins to contact the water, run a stopwatch to time it. When the powder on the water surface is completely wetted, that is, when there is no white substance, stop timing, and this time interval is the wetting time. The criterion for judging complete wetting is that the copolymer thickener powder has no white spots or only one or two small white spots on the water surface, and the white spots stuck on the wall of the beaker are not considered.

2. 1.8% hydrogel skin sensory evaluation test

1 Select subjects

Select 20 subjects, aged 18-40, half male and half male. The subjects were required to have healthy skin and no history of skin diseases or allergies.

2 test sites

Select an appropriate area of the subject's anterior wrist flexion area as the test area, rinse the test area with pure water for 30 seconds before the test and let it dry naturally.

3 operation method

3.1 Gel Evaluation

The subjects touch the tested gel with their index finger to feel the elasticity of the gel; stick the gel with their index finger to observe the sticking amount of the gel when sticking; observe the fineness of the gel.

3.2 Evaluation of skin feel during rubbing

Take an appropriate amount of the tested gel with your index finger, rub it back and forth on the test area, and feel the spreadability, slipperiness and degree of dehydration of the gel during the rubbing process.

3.3 Skin feel evaluation after drying

After rubbing evenly, wait for the gel to dry, feel the drying speed and the film-forming feeling after drying.

4 scoring rules

The subjects rated the above evaluation items according to Table 9.

Table 9 Skin feel test scoring rules

Test Results

The data obtained after the above-mentioned various embodiments and comparative examples are tested according to the above-mentioned test method are shown in Table 10 and Table 11.

The wetting time test result of table ten embodiment A1 to A6, comparative example A1 and A2

Comparative example 2 has a longer wetting time, and is limited to complete wetting on the surface, and there are white agglomerates inside.

At the same time, this test experiment also attaches the graphs of dispersion performance shown in Figure 1, Figure 2 and Figure 3.

Take the commercially available N-vinylpyrrolidone/acrylic acid cross-linked copolymer and the product of Example A2 to compare the wetting and dispersing properties. The test method is as follows:

Step 1: Test according to the above wetting time test method, observe the wetting condition of the two after feeding for 10 minutes and take pictures;

Step 2: Put the above sample under an electric mixer at a speed of 500rpm and stir for 30min, observe the dispersion of the two and take pictures;

Step 3: Adjust the rotational speed to 350 rpm, add 0.6 g of 18 wt % NaOH solution each, observe the gel formed after the neutralization of the two and take pictures.

The surface tension of water can be effectively reduced after the product of embodiment A2 is dropped into water, so it can spread rapidly on the water surface. As shown in Figure 1, after 10 minutes, it was completely wetted and moderately swelled into a semi-permeable gel; the comparative commercial sample could not reduce the surface tension of the water after being put into water, and gathered into agglomerates, and only the surface of the powder was wet after 10 minutes .

As shown in Figure 2, after stirring at 500 rpm for 30 minutes, the product of Example A2 was completely dispersed in water, forming a uniform dispersion; while the commercially available product could not form a uniform dispersion.

As shown in Figure 3, the product of Example A2 is quickly neutralized after adding alkali, and can form a uniform, viscous transparent gel after stirring for 2 minutes (the content of the gel in Figure 3 is the air bubbles brought in during stirring); However, the neutralization of the commercially available product after adding alkali is very slow. With the progress of the neutralization reaction, the white insoluble matter decreases slowly, and the viscosity of the gel increases slowly. After stirring for 15 minutes, there are still a large amount of unneutralized white flocs in the gel.

Table 11 The skin feel evaluation results of Examples A1 to A6, Examples B1 to B6 and Comparative Examples A1 and A2

From the above test results, it can be found that the surface of the polymer copolymerized with only N-alkylacrylamide is too hydrophobic, and it is difficult to wet and disperse; while Examples A1-A6 all have a short wetting time and are easy to disperse. Adding N-alkylacrylamide and N-vinylpyrrolidone to carry out copolymerization gel sample, its gel elasticity, stickiness score is much higher than adding N-alkylacrylamide to carry out copolymerization gel sample (comparative example A1 ), and the degree of hydration is very low, it is not easy to become thin when applied on the skin, and it has a good film-forming feeling after drying. The gel sample (comparative example A2) that only adds N-vinylpyrrolidone for copolymerization has poor gel elasticity and slipperiness when applied, becomes slightly thinner when applied, dries slowly and feels sticky.

The above are only preferred embodiments of the present invention, and any modifications, equivalent replacements and improvements made within the spirit and scope of the present invention shall be included within the protection scope of the present invention.

Claims (9)

1. A skin care composition, characterized in that it comprises (0.1 to 3) wt% carboxylic acid copolymers used as rheology modifiers and film formers, and said carboxylic acid copolymers are poly(α , β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer and/or poly(α,β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer ; In the poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide/N-vinylpyrrolidone) cross-linked copolymer, α, β-unsaturated carboxylic acid, N-alkylacrylamide and N- The mass ratio of vinylpyrrolidone is 65-87:3-18:4-25; The mass ratio of α, β-unsaturated carboxylic acid and N-alkylacrylamide in the poly(α, β-unsaturated carboxylic acid/N-alkylacrylamide) cross-linked copolymer is 75-95:6 ~18. 2. The skin care composition according to claim 1, characterized in that, the skin care composition is skin care gel, anti-wrinkle composition, skin care lotion, skin care ointment/cream. 3. The skin care composition according to claim 1, characterized in that the composition comprises an appropriate amount of neutralizing agent, other cosmetic and/or skin care products acceptable bases and the balance of deionized water. 4 . The skin care composition according to claim 1 , wherein the chemical formula of the alkyl group in N-alkylacrylamide is C _n H _2n+1 , where n=4-12. 5. The skin care composition according to claim 4, wherein said N-alkylacrylamide is N-dodecylacrylamide, N-octylacrylamide, N-tert-octylacrylamide One or more combinations of amide, N-heptylacrylamide, phenylacrylamide, N-butylacrylamide, N-tert-butylacrylamide. 6. skin care composition according to claim 4, is characterized in that, described α, β-unsaturated carboxylic acid is (meth)acrylic acid, crotonic acid, maleic acid, fumaric acid, itaconic acid one or a combination of more. 7. The skin care composition according to claim 4, wherein said α,β-unsaturated carboxylic acid is acrylic acid. 8. The skin care composition according to claim 4, characterized in that the cross-linking monomer used in the carboxylic acid copolymer accounts for 1.0-3.2 wt% of the total weight of the comonomers. 9. The skin care composition according to claim 8, wherein the cross-linking monomer is one of pentaerythritol triallyl ether, diethylene glycol diallyl ether or sucrose allyl ether one or more combinations.